


Filling the Void

by lesbianpapyrus



Category: Undertale (Video Game)
Genre: Birthday, Gen, M/M, Multi, Slice of Life, papyrus does the planning and everyone else goes along for the ride
Language: English
Status: Completed
Published: 2018-04-24
Updated: 2018-04-24
Packaged: 2019-04-27 11:50:31
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,229
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14424816
Author URL: https://archiveofourown.org/users/lesbianpapyrus/pseuds/lesbianpapyrus
Summary: It's the first birthday Gaster has had since coming back from the void, and his family makes sure it's the best one he's ever had.





	Filling the Void

**Author's Note:**

  * For [250mb](https://archiveofourown.org/users/250mb/gifts).



> for the best brother I've ever had.

“DAD! Dad, wake up! Wake up, wake up, wake up wake up WAKE UP!”

Gaster started violently out of a deep sleep and grabbed the cane standing next to his bed, waving it wildly. “Papyrus! What’s wrong? What’s going on? Are the humans attacking?!”

Papyrus scrambled off his father toward the back of the bed to avoid the flailing cane and put his hands up. “No, Dad! It’s okay, nobody is attacking! It’s just me.” He smiled. “And we’re on the surface now, remember? The humans are our friends.”

Gaster blinked and let his cane fall to the bed. “Then why all the yelling?” he grumbled, feeling for his glasses on the bedside table.

His father’s irritability wasn’t lost on Papyrus, and his smile dropped away. “It’s… it’s your birthday today,” he faltered. “Don’t you remember?”

 _My birthday._ Gaster had spent so long in the void, the concept of birthdays was almost foreign to him. The passage of time wasn’t really a concern of yours when you technically didn’t exist.

But now he was back in reality, and birthdays were a thing again. This would be his first one since his sons and their weird time-reversing human friend had rescued him and introduced him to the world outside the Underground.

“Oh, dear…” Gaster sat up and rubbed his head. “I’m afraid… I’m afraid I didn’t remember. I don’t even know how old I’m supposed to be…”

“It’s okay.” Papyrus smiled gently again. “Sans and I know. You’re fifty-one! Just over twice as old as I am.”

Fifty-one. That meant he’d spent over fifteen years in the void, and fifteen years out of his sons’ lives.

Papyrus had been less than ten years old when he’d last seen his father before the accident.

“Oh, no, Dad, no—please don’t cry—” Papyrus reached forward, and Gaster suddenly felt the tears falling down his cheekbones.

He wiped them away quickly. “I’m alright, Papyrus, I promise. It’s just…” He smiled sadly and sighed. “I guess I’m realizing all over again that my little boy is all grown up… and I missed getting to watch it.”

Papyrus blinked, then shook himself. “Well, as tragic as it is that you’ve missed most of the life of the Great Papyrus… today is not about me! It’s about you! So get on up and put some clothes on!” He leaped off the bed and threw open the curtains in front of the window. “We have a lot planned for today and you’re not going to miss a single bit of it!”

“Alright, alright… you go ahead down, I’m going to need some time to change.” Gaster swung his legs off the bed with some effort. “I’m afraid I still move like I’m stuck in goop.”

“Okay! See you down there soon, then!” Papyrus disappeared out of the bedroom.

Gaster took nearly half an hour to change into his old gray sweater and pants and clean up. After washing his face in the bathroom, he gazed at his reflection in the mirror, vaguely tracing the two large cracks in his face that ran from the bottom of his left eye socket to his upper jaw and from the top of his right eye socket all the way over his skull—scars left over from the void, scars that would never heal. The longer he looked, the bigger the void in his heart felt. Nothing would ever be the same as before, he knew—not his life, not his family, not even his appearance.

He didn’t realize how long he’d been staring at himself until someone knocked on the door. “Dad? You okay in there?”

Gaster shook himself and called out, “Yes, Sans! I’ll be out in a minute.”

“Okay, just checkin’. Hurry up or your waffles are gonna get cold.”

Waffles? Gaster felt a smile coming on. After all these years, his sons still remembered his favorite breakfast.

He just hoped Papyrus wasn’t cooking them.

Fortunately, Gaster found that he was not. As soon as he stepped into the kitchen, he felt the unusual heat and smelled the delicious, not-burned scent of Belgian waffles, he knew exactly who was doing the cooking.

“Grillby,” Gaster said with a smile.

Gaster’s longtime partner left the stove and came to embrace him, his flames flaring blue with happiness and contentment. Gaster let Grillby’s warmth consume him, let his own flame of passion from the past overtake him—

“Hey, Grillbz, when you’re done with your lovefest over there, your food is burning,” Sans interrupted, grinning.

“Be quiet, Sans! Let the old people have their fun,” scolded Papyrus, but he was grinning, too.

Gaster squinted at both of them. _“Both_ of you shut your mouths or you’ll be spending the day in your rooms.”

“Keep dreamin’, Dad. Anyway, guess _I’ll_ rescue your waffles.” Sans opened the waffle iron and checked the damage.

“We can’t spend the day in our rooms! Then you’d miss all the fun, because we planned everything today!” Papyrus cried indignantly. “Besides, we’re not children anymore.”

Gaster did not need that reminder. “I know, son. I was joking.” He tried not to sound troubled, but Papyrus seemed to sense he’d said something off, anyway.

“Well—well! Let’s just get those waffles on the table, Sans.” Papyrus reached over his brother and slid one of the waffles onto a plate. “Dad gets the first one!”

Breakfast was an enjoyable affair. Gaster doused his waffle with butter and maple syrup just like he used to do. In a few minutes, the other three joined him around the table, and they all ate quietly, occasionally asking for a condiment or getting up for more food. When they were finished, Papyrus and Grillby did the dishes, insisting that Gaster rest.

Sans turned to his father. “Papyrus has the whole day planned out. You’re definitely gonna wanna rest now,” he said in a low voice.

Gaster only smiled, having learned by now that planning days full of activities was how Papyrus often showed love.

Outside, the April day was unusually cool and cloudy, but that did not deter Papyrus from his plans. “Everybody put on your coat and let’s go!” he said with optimism, ushering Gaster and the others into the front hall. “Go on out to the car, I’m just going to put something together and then we’ll leave!”

Gaster took the front passenger seat in Papyrus’s car while Sans and Grillby took the back, and they all waited while Papyrus made a big show of hiding and securing something in the trunk. Then they were off.

“Where are we going, son?” Gaster asked curiously as Papyrus got on the highway.

“Nowhere! We’re just going for a drive around the city. We will be stopping somewhere later, though. And I’m sure you’ll like it very much!” Papyrus said brightly, keeping his eyes on the road.

No matter how much Gaster bugged him, Papyrus would not reveal any of their future destinations, and his father was forced to sit back and just enjoy the ride. Fortunately, that wasn’t too difficult.

For quite a while they drove all around the city with Papyrus and occasionally Sans acting as tour guides, pointing out historic buildings and gardens, good places to eat, stores they liked to shop at, and sometimes people doing interesting things on the street. Gaster was greatly impressed; never had he seen a place so busy and alive. Not even the Capital back in the Underground had been so crowded.

Eventually they crossed over a great bridge to a more rural part of town, with farms and wheat fields and forests. Papyrus turned onto a dirt road and drove up a little way to a small clearing in the middle of a forest, where he finally parked. “Everybody out! We’re walking from here on out.”

Outside the car, the other three watched in awe as Papyrus pulled a large picnic basket and blanket from the trunk. “Jeez, Paps, you really went all out, didn’tcha?” commented Sans once he’d gotten his voice back.

Papyrus beamed. “Of course! Only the best for my favorite dad!” He pointed ahead to a small trail through the woods. “We’re headed up that way. We can go as slow as you need, Dad.”

As it turned out, Gaster needed to go pretty slowly, as it was difficult to find his footing and place his cane down where it wouldn’t slip. No one was perturbed, however, and Papyrus used the time to describe the plants and wildlife surrounding them.

Finally, they arrived at a large lake with pretty dark blue water, rippling with the activity of fish and insects. Papyrus set down the blanket and began pulling various containers and wrapped foods out of the basket, including beef sandwiches, fruit salad, carrots and celery, corn chips, and chocolate cookies.

Gaster stared at the delicious-looking ensemble. “How long did it take you to—we were only waiting for you in the car for a few minutes this morning!” he said eventually, shaking his head.

“Oh, I made it all at 3:30 this morning and then put it all in the refrigerator until we left,” Papyrus answered with no trace of a joke in his voice.

Gaster blinked and then shrugged, figuring that by now he should probably be used to his son’s odd mannerisms. He got himself a plate of food, leaned on Grillby’s shoulder, and listened to Papyrus babble on about the lake.

“Sans and I went fishing here once. I wanted to go fishing today since humans consider that the epitome of father-son activities. But we don’t have any fishing rods at home, and we got banned from the rental business because _someone—”_ Papyrus narrowed his eyes at Sans, who went slightly blue in the face. “—couldn’t keep his hook to himself.”

“That was _not_ my fault,” Sans grumbled.

“It was abso-posi-lutely one-hundred percent your fault, Sans. Anyway, I figured you’d still enjoy being near the water and eating outside,” Papyrus said to Gaster.

Gaster chuckled and settled back into Grillby’s shoulder, somewhat comforted by the fact that his sons still had boyish spats now and then, even at their age. He’d almost missed that back in the void.

Only about ten or so minutes had passed when the first crack of thunder rolled over them. The little family looked up at the sky, which had turned from a simple light gray to dark and threatening. The skeletons all looked at Grillby, who looked very nervous at the thought of a rainstorm.

They threw everything helter-skelter into the basket and ran back to the car as fast as they could, Papyrus and Grillby almost carrying Gaster and Sans. Just as they got back into the car, the skies began pouring rain.

“Guess we got back just in time,” Sans panted as he stared out the window. “Hey—hey, Papyrus, are you okay?”

Papyrus had started to sniffle as soon as he was settled in the car, and now the sniffling was turning to full sobbing. “I-It’s ruined!” he cried, covering his face. “The whole day is ruined! I had everything planned out—it w-was going to be a nice picnic—and now it’s all ruined!”

“Hey, Paps, it’s not the end of the world, we can finish eating in here and then do whatever you had planned next,” Sans tried to soothe, rubbing his shoulder. He looked at his father concernedly. “He gets like this when his plans are interrupted, he’ll be okay in a little bit…”

Gaster looked over at Grillby, who shrugged sadly. The fire monster then reached out and rubbed Papyrus’s other shoulder comfortingly.

Gaster took his younger son’s hand. “Son, look at me.”

With difficulty and shame, Papyrus lifted his eyes and faced his father.

“I have had a _wonderful_ time today,” said Gaster firmly. “There is no other way I would like to spend my birthday than just being with my family, especially after being lost to the universe for so long. I’m so happy that you’ve been able to show me the surface world, and proud that you know so much about it, and touched that you care so much about me enjoying myself.” He smiled. “Not a thing has been ruined. As Sans suggested, we can finish our lunch here, and then I will be more than content enough to go do whatever you have planned next.”

Papyrus smiled tearfully, then exhaled and wiped his eyes. “You’re right, I’m being ridiculous. I’m sorry.”

“It’s alright.” Gaster dug into the picnic basket and pulled out the container of celery. “Have something more to eat. You know, I’m a bit surprised you packed celery. I recall you not liking it very much when you were young.”

“Of course I eat it now! You can’t grow up strong and healthy without your greens.” Papyrus took the celery and bit into it, making a face. “That does not mean it has a pleasant taste, however.”

Everyone laughed a little, the good mood of earlier restored. They finished their meal, and Papyrus carefully navigated the car back to the main country road and began to head back for the city.

“You seem especially excited about this, Papyrus. What are we doing?” Gaster asked curiously, noting his son’s drumming fingers on the steering wheel and jiggling legs.

“We’re gonna see his boyfriend’s new movie. Gay romantic comedy, you’ll probably enjoy it,” answered Sans.

“Sans! You weren’t supposed to spoil it!” Papyrus yelled angrily, glaring at him in the rearview mirror. “But yes, Dad, he is correct. We are going to see Mettaton’s new movie. It’s supposed to be lighthearted and funny, and I also thought you might enjoy sitting in a dark room next to your boyfriend for two and a half hours. I know _I_ definitely do.”

“You what? Enjoy sittin’ in a dark room next to Grillby? Mettaton’s not gonna like that.”

_“SANS!”_

“Kidding!”

“Boys, boys,” Gaster chided distractedly, trying to ignore the fake-sultry looks Grillby was throwing his way in the mirror. “You stop that!” He finally turned and shook a finger at Grillby. “You—” He dissolved into laughter, his face growing pink with embarrassment. “Sans, make him stop!”

“He’s _your_ boyfriend, I ain’t got any control over him.” Sans put his hands up as Grillby started making kissing noises.

“ENOUGH! Or we’re going home! Grillby, save it for the theater!” Papyrus scolded.

However, once they had gotten their tickets and snacks and were sitting down in the theater, Gaster and Grillby were more than content to just lean on each other and occasionally nuzzle as they watched the movie. The film itself turned out to be pretty good, with fantastic acting from Mettaton and his costars, emotional music, a compelling romance, and a surprisingly suspenseful climax and satisfying ending.

“Wasn’t that great? Mettaton took me to the midnight premiere like he always does. He suggested I take you to see it today. Did you like it? I can buy it for you when it comes out!” babbled Papyrus at Gaster as they walked back to the car afterward.

“It was very good. I was certainly entertained.” Gaster smiled, then leaned heavily on Grillby. “Ugh, I’m getting very tired. And it’s getting pretty late,” he said, noting how dark it was getting.

“Oh… do you want to go home now? I had one more thing planned, but if you really want…” offered Papyrus uncertainly, wringing his hands.

Gaster exhaled, not liking to disappoint his son. “What is it?”

“Just dinner at a sit-down restaurant. It might be a little busy, but you won’t have to do much. And we can go home straight after.”

“Alright,” Gaster sighed. “I suppose as long as it’s slow.”

“Right then!” Papyrus bounded to the driver’s side of his car, energy renewed. “Here we go!”

They drove for only a few minutes, and then Papyrus pulled into the parking lot of a Waffle House and beamed proudly.

“Pap, we, uh… had waffles for breakfast this morning,” Sans sighed.

“You don’t have to get them again if you don’t want them! I just thought Dad might like the opportunity to have more,” explained Papyrus, looking over to Gaster for affirmation.

Gaster shrugged. “I do love waffles. I’m just not sure how much more I can eat today.”

“You can get whatever you want! I’m paying.”

“Well, technically _I’m_ paying, since I take care of the credit card bills,” Sans chuckled in a low voice to his father. “But Pap makes most of the money… so I guess he’s not wrong.”

As Papyrus had predicted, the restaurant was busy, but they didn’t have to wait long for a table or menus. Gaster ordered waffles again, and Sans followed suit, resulting in Papyrus scolding him, “If you were going to just order waffles again, why did you complain about coming here?!” Grillby and Papyrus both ordered off the dinner menu, asking for a cheeseburger and a grilled chicken sandwich respectively.

As they waited, Sans decided to torture them all with skeleton puns until Papyrus threatened to leave him at the restaurant. After that, the air between them all was filled with quiet banter and conversation until they received their food, paid the bill, and packed up the leftovers to go home.

The ride back was quiet, but comfortable. Gaster closed his eyes and thought about how lucky he was to have two loving sons and a wonderful boyfriend who were willing to take him out and about like this, to make sure he enjoyed his birthday.

His thoughts were interrupted by Sans. “So who’s ready for cake and presents?”

“Oh, god,” Gaster groaned. “I couldn’t eat one more thing. And bed is the best gift I could possibly receive right now.”

“But cake and presents are the most basic tenets of good birthdays!” Papyrus exclaimed indignantly as they pulled up in the driveway of their house. “I guess we can save the cake for later if you really want. But opening presents doesn’t require a lot of energy. And besides, I think you’ll quite enjoy what we’ve gotten for you.” He looked at his father with puppy-dog eyes. “Please, Dad?”

Gaster laughed. “Alright, alright. I’ll open the gifts. But I might need a nap between that and cake.”

“Okay!” Papyrus came around to his side and helped him out of the car. “You’re gonna love it! I can hardly keep myself from spoiling it all!”

As all of them walked up to the front door, Gaster couldn’t help but pull the other three into his arms and gently clack his jaw against his sons’ heads. “I love you all so much. Thank you for everything.”

“Of course! We’d do anything for you!” Papyrus snuggled into Gaster’s shoulder.

“Yeah, anything,” agreed Sans, his voice much warmer than it usually was.

Grillby rubbed Gaster’s back, his own act of affirmation.

Then they all went inside. As he listened to Papyrus’s constant chatter, Sans’ occasional deep tones, and the crackle of Grillby’s flames, Gaster realized he wouldn’t want to be anywhere else in the world right now, not even in bed. His exhaustion now outmatched by his excitement, he followed them into the kitchen with vigor, eager to see what future treasurable moments the universe had in store for him and his family.

The void that had opened up in his heart was finally filling up again.

**Author's Note:**

> BRO BROOOOOOOOOOOOOOOOOOOOOOO HAPPY BIRTHDAY PLEASE IGNORE THE FACT THAT THIS IS 22 DAYS LATE
> 
> I love you so much and I'm so glad I had the opportunity to write for you, as long as it took me to get it done. you mean so much to me and I hope this story reflects that.


End file.
